// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "esp32-hal.h"
#include "lwip/apps/sntp.h"
#include "tcpip_adapter.h"

static void setTimeZone(long offset, int daylight)
{
    char cst[17] = {0};
    char cdt[17] = "DST";
    char tz[33] = {0};

    if(offset % 3600){
        sprintf(cst, "UTC%ld:%02u:%02u", offset / 3600, abs((offset % 3600) / 60), abs(offset % 60));
    } else {
        sprintf(cst, "UTC%ld", offset / 3600);
    }
    if(daylight != 3600){
        long tz_dst = offset - daylight;
        if(tz_dst % 3600){
            sprintf(cdt, "DST%ld:%02u:%02u", tz_dst / 3600, abs((tz_dst % 3600) / 60), abs(tz_dst % 60));
        } else {
            sprintf(cdt, "DST%ld", tz_dst / 3600);
        }
    }
    sprintf(tz, "%s%s", cst, cdt);
    setenv("TZ", tz, 1);
    tzset();
}

/*
 * configTime
 * Source: https://github.com/esp8266/Arduino/blob/master/cores/esp8266/time.c
 * */
void configTime(long gmtOffset_sec, int daylightOffset_sec, const char* server1, const char* server2, const char* server3)
{
    tcpip_adapter_init();  // Should not hurt anything if already inited
    if(sntp_enabled()){
        sntp_stop();
    }
    sntp_setoperatingmode(SNTP_OPMODE_POLL);
    sntp_setservername(0, (char*)server1);
    sntp_setservername(1, (char*)server2);
    sntp_setservername(2, (char*)server3);
    sntp_init();
    setTimeZone(-gmtOffset_sec, daylightOffset_sec);
}

/*
 * configTzTime
 * sntp setup using TZ environment variable
 * */
void configTzTime(const char* tz, const char* server1, const char* server2, const char* server3)
{
    tcpip_adapter_init();  // Should not hurt anything if already inited
    if(sntp_enabled()){
        sntp_stop();
    }
    sntp_setoperatingmode(SNTP_OPMODE_POLL);
    sntp_setservername(0, (char*)server1);
    sntp_setservername(1, (char*)server2);
    sntp_setservername(2, (char*)server3);
    sntp_init();
    setenv("TZ", tz, 1);
    tzset();
}

bool getLocalTime(struct tm * info, uint32_t ms)
{
    uint32_t start = millis();
    time_t now;
    while((millis()-start) <= ms) {
        time(&now);
        localtime_r(&now, info);
        if(info->tm_year > (2016 - 1900)){
            return true;
        }
        delay(10);
    }
    return false;
}

